1. Filed of Invention
The present invention relates to wireless communication, more particularly, to a method for identifying a connection in the connection-oriented MAC, a mobile station and a base station.
2. Description of Prior Art
With the rising requirements on broadband wireless communication, IMT-advanced being conducted by the International Telecommunications Union-Radio Communications Sector (ITU-R) has attracted more and more interests from researchers and companies all over the world. The standard IEEE 802.16m is intended to be a candidate for consideration in the IMT-Advanced evaluation process. Thus, IEEE802.16m shall meet the IMT-Advanced performance requirements, such as higher peak rates, lower system overhead as well as QoS and radio resource management (RRM).
As IEEE 802.16m is at the initial stage of standardization, all the technical solutions have not been defined, As proved in IEEE 802.16d/e, connection-oriented MAC is a good choice to support QoS classes, enabling an optimal matching of service, application and protocol requirements to radio access network (RAN) resources and radio characteristics. However, overhead for all applications shall be reduced as far as feasible without compromising overall performance and ensuring proper support of systems features.
In the standard of IEEE 802.16 D/E, a 16-bit value called CID is used to identify a connection in the medium access control layer (MAC) of the base station (BS) and subscriber station (SS). The CID address space is common (i.e., shared) between UL and DL and partitioned among the different types of connections. All the transported data blocks should be encapsulated as the form of MAC PDUs. As shown in FIG. 1, MAC header contains a 16-bit CID field to map those data to connections. In addition, the CID is also used by Base Station to allocate radio resources to MS or connection.
However, the scheme proposed in IEEE 802.16d/e has the shortcomings as follows. Overhead of MAC PDU introduced by CID is not minimal, and will waste too much radio resource due to high frequency use.
In addition, the BS should guarantee that the CID value is unique in one cell or sector, Which will make some control mechanisms more complex in some cases. For example, when one MS perform the handover operation from source BS to target BS, if there are active connections in the MS, the target BS should reassign new CID values for all these connections. This will again augment the overhead of control signaling.